<!DOCTYPE html 
     PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xml:lang="fr" lang="fr" xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> 
 <title></title> 
 <link rel="stylesheet" type="text/css" href="stylesheet_appli.css" /> 

</head> 
<body id='body' > 
<script> 
function plus()  

{  

document.getElementById('demande').innerHTML += '<tr><td>test</td><td>test</td><td>test</td></tr>'  

}  
</script> 
<table id='demande'> 
<tr> 
 <td>test</td> 
 <td>test</td> 
 <td>test</td> 
</tr> 
</table> 
<input type='button' value='Ajouter une ligne' onClick='plus()' />
</body> 
</html>